If A = [a11 a12] and B = [a21 a22] are arbitrary vectors in IR^2, then the mapping (A, B) = a11b11 + a12b12 + a21b21 + a22b22 defines an inner product in IR^2. Use this inner product to determine (A, B), |A|, |B|, and the angle θ between A and B for A, B ∈ IR^2.